I'll second what the previous poster said: I don't eat my chickens. That's not because I don't like chicken, but because there are easier ways for me to attain sustainability than chicken only. I have a mixed flock, and I average half a dozen eggs a day from my 7 hens, slowing in winter. Given the cost of raising them from day-old peeps, replacing them when the time comes isn't a large concern for the wallet.
As I've continued building out the homestead, though, I've incorporated rabbits as the main meat source. They're leaner, higher in protein, and require only a couple square feet of space to live. Given the size of your plat of land, consider branching out to other things besides chickens. I think all of us (I know this is true for me) start with chickens, because they just seem logical. But at this point, I'm adding ducks to the homestead, too, as they're layers on par with chickens (and in some cases better), are better at brooding and raising their own ducklings (which goes a long way in my book), and provide that dual-purpose rotation you described wanting.